This disclosure generally relates to the art of vehicle suspension systems and, more particularly, to a system and method of sensing a load on a vehicle having non-fluid springs.
The present novel concept finds particular application and use in conjunction with suspension systems of wheeled vehicles, and will be described herein with specific reference thereto. However, it is to be appreciated that the present novel concept is also amenable to use in other applications and environments, and that the specific uses shown and described herein are merely exemplary.
As vehicles, such as relatively light-duty wheeled vehicles (e.g., passenger vehicles, pick-up trucks and sport utility vehicles), continue to advance in complexity and sophistication, the systems thereof make greater and greater use of data, signals and/or information relating to performance and other conditions (e.g., speed, acceleration, vehicle height, vehicle orientation) of a vehicle as well as the various inputs (e.g., road impact forces) acting thereon. Such data, signals and/or information may be utilized by systems such as automatic braking systems, traction control systems and stability control systems, tire pressure monitoring systems and/or central tire inflation systems, for example.
One additional input or condition of a vehicle that can be utilized by such systems is the external load acting on the vehicle, such as from passengers and/or cargo. Vehicles having air spring suspension systems are well known, and are generally well suited for determining a load of the sprung mass of the vehicle. Normally, the operational components of such an air spring suspension system will be capable of generating a signal indicative of or otherwise having a relation to the overall weight of the sprung mass at any given time.
Unfortunately, comparatively few vehicles are outfitted with air spring suspension system. Rather, the great majority of light-duty vehicles include suspension systems that utilize non-fluid springs. Such non-fluid springs are typically formed from metal, such as steel, for example. Additionally, such non-fluid springs are normally of a well known type and/or construction, such as coil springs, leaf springs or torsion springs, for example. However, due to the nature and operation of suspension systems with non-fluid springs, such systems typically do not include components suitable for use in load determination. As such, vehicles that include systems that utilize data, signals and/or information having a relation to a load on a vehicle typically include an air spring suspension system. As an alternative, such systems may operate using data, signals and/or information other than that relating to the vehicle load condition.
One example of a use or application in which it may be desirable to determine and utilize the value of an approximate load on a vehicle involves the optimal inflation of the vehicle tires. Light-duty vehicles, such as those discussed above, are commonly outfitted with dual-placard tires, which are designed for operation at two different pressure levels. One pressure level is typically used for normal or relatively light vehicle loads, and the second pressure level is generally intended for use when the vehicle is more heavily loaded.
One difficulty with known light-duty vehicles that utilize such dual-placard tires is that the suspension system of such vehicles commonly include non-fluid springs, as discussed above. Such suspension systems, as installed, are generally incapable of determining a value of the approximate load on the vehicle or communicating such an approximate load to a vehicle system or to the vehicle operator. As such, the vehicle operator is usually without any practical means of determining the approximate value of a load on the vehicle. Therefore, the vehicle operator usually cannot easily determine which of the two pressure ranges of such dual-placard tires should be used. As a result, the vehicle operator may not change the air pressure in the vehicle tires in accordance with the load conditions on the vehicle. This can undesirably lead to sub-optimal performance, handling and/or rider comfort of the vehicle.
Accordingly, it has been considered desirable to develop a system and a method operative to overcome the forgoing and other problems and/or difficulties.